Some of the information disclosed and claimed in this application is also disclosed in a commonly owned, co-pending application entitled: Electronics Module for the Control and Diagnostics of Automobile Signal Lamps, U.S. Ser. No. 09/096,018 filed on even date herewith by Angela D. Magruder.
This invention relates to automobile lamp systems, and more particularly to the performance monitoring of automobile brake signal lamps.
With the significant advances in automobile performance, there have been corresponding improvements to occupant safety as well as to vehicle service and repair. This includes improved occupant safety devices, improved vehicle crash worthiness, and improved engine reliability. One element of these improvements has been the added electronic content of the automobile operating systems; both control and fault diagnosis. The leading application for developing electronic content has been in connection with control of engine performance; primarily directed toward reduced emissions, but increasingly used to provide improved engine diagnostics. This allow for more accurate repairs and also provides forewarning to the operator of potential engine failure. All of this results in greater security to the automobile occupants as well as better repair programs.
One aspect, however, of the automobile""s operating systems that has not received as many advances in technology is the vehicle brake lamp subsystem. The proper functioning of this system is important to vehicle and occupant safety as well as to the safety of other drivers. Notwithstanding the past improvements and reliability of this system it remains fundamentally the same in terms of its electromechanical operation. The brake lamp system is actuated with closure of a brake switch connected to the brake pedal, such that when the brake pedal is depressed the switch closes and applies 12 VDC to the brake lamps. While this system has high reliability due to its simplicity, there is no immediate notice to the driver of a failure in the brake lamp system. Such a failure could include a failed switch which, although the braking system operates, fails to provide the excitation voltage to the lamps. Alternatively, a common problem is burn out of one or more of the brake lamps. These failures generally take time to discover and are usually determined by verbal warnings from other parties.
One object of the present invention is to provide apparatus for providing automated performance monitoring of a motor vehicle""s brake lamp system. Another object of the present invention is to provide automated recording of a failed brake lamp condition and to facilitate technician access to these records during service maintenance. Still another object of the present invention is to provide an automated warning to the vehicle operator/occupant of a failed brake lamp condition.
According to the present invention, a microprocessor based control detects actuation of the vehicle""s braking system and senses the actual magnitude of the lamp current drawn by the system""s brake lamps during illumination; the microprocessor having a memory for storing signals, including a plurality of reference signals indicative of the nominal value of brake lamp excitation current required for illumination of a full compliment of brake lamps as well as the current value nominally associated with successively lesser numbers of operating lamps; the microprocessor comparing the sensed actual magnitude of the lamp current with each of the reference signals to determine the presence and number of inoperative lamps.
In further accord with the present invention the microprocessor stores in memory the number of inoperative lamps detected. In still further accord with the present invention, the microprocessor based control includes interface circuitry which is operatively connected to the microprocessor and is also adapted for operative connectability to external equipment to permit the automated read-out of recorded lamp failure messages to be used in the servicing of the vehicle. In still further accord with the present invention the microprocessor based control also provides a visible and or audible warning to the operator of inoperative brake lamps.
The present invention provides for intelligent means to monitor the performance of a motor vehicle""s brake signaling system. The system includes detection and reporting of failure modes in lamp excitation to permit efficient repair, as well as providing real time alarms to the vehicle operator in the event of a signal device failure constituting a safety failure condition.
These and other objects, features, and advantages of the present invention will become more apparent in light of the following detailed description of a best mode embodiment thereof; as illustrated in the accompanying Drawing.